pkg/bisect: check existence of input files

It's better to fail early then to wait for kernel build.

Update #501

2 files changed, 24 insertions, 1 deletions

diff --git a/pkg/bisect/bisect.go b/pkg/bisect/bisect.go
index c78508368..df5dfcd90 100644
--- a/pkg/bisect/bisect.go
+++ b/pkg/bisect/bisect.go
@@ -64,6 +64,9 @@ type buildEnv struct {
 }
 
 func Run(cfg *Config) (*vcs.Commit, error) {
+	if err := checkConfig(cfg); err != nil {
+		return nil, err
+	}
 	repo, err := vcs.NewRepo(cfg.Manager.TargetOS, cfg.Manager.Type, cfg.Manager.KernelSrc)
 	if err != nil {
 		return nil, err
@@ -337,9 +340,26 @@ func (env *env) saveDebugFile(hash string, idx int, data []byte) {
 	if env.cfg.DebugDir == "" || len(data) == 0 {
 		return
 	}
+	osutil.MkdirAll(env.cfg.DebugDir)
 	osutil.WriteFile(filepath.Join(env.cfg.DebugDir, fmt.Sprintf("%v.%v", hash, idx)), data)
 }
 
+func checkConfig(cfg *Config) error {
+	if !osutil.IsExist(cfg.BinDir) {
+		return fmt.Errorf("bin dir %v does not exist", cfg.BinDir)
+	}
+	if cfg.Kernel.Userspace != "" && !osutil.IsExist(cfg.Kernel.Userspace) {
+		return fmt.Errorf("userspace dir %v does not exist", cfg.Kernel.Userspace)
+	}
+	if cfg.Kernel.Sysctl != "" && !osutil.IsExist(cfg.Kernel.Sysctl) {
+		return fmt.Errorf("sysctl file %v does not exist", cfg.Kernel.Sysctl)
+	}
+	if cfg.Kernel.Cmdline != "" && !osutil.IsExist(cfg.Kernel.Cmdline) {
+		return fmt.Errorf("cmdline file %v does not exist", cfg.Kernel.Cmdline)
+	}
+	return nil
+}
+
 func (env *env) log(msg string, args ...interface{}) {
 	fmt.Fprintf(env.cfg.Trace, msg+"\n", args...)
 }
diff --git a/tools/syz-bisect/bisect.go b/tools/syz-bisect/bisect.go
index ec68f4b95..eaae1f9e7 100644
--- a/tools/syz-bisect/bisect.go
+++ b/tools/syz-bisect/bisect.go
@@ -78,7 +78,10 @@ func main() {
 	loadFile("kernel.config", &cfg.Kernel.Config)
 	loadFile("repro.syz", &cfg.Repro.Syz)
 	loadFile("repro.opts", &cfg.Repro.Opts)
-	bisect.Run(cfg)
+	if _, err := bisect.Run(cfg); err != nil {
+		fmt.Fprintf(os.Stderr, "bisection failed: %v\n", err)
+		os.Exit(1)
+	}
 }
 
 func loadString(file string, dst *string) {